1. Field of the Invention
The present invention relates to an apparatus for cleaning the toner remaining on a toner retaining member after transfer of a toner image, in a recording apparatus such as an electrophotographic copying apparatus and an electrostatic recording apparatus. More particularly, the invention relates to an improvement of a toner guide member which guides toner removed from a toner retaining member to a toner reservoir or to a toner conveying means normally arranged in a place apart from said toner retaining member.
2. Description of the Prior Art
There has so far been known the fact that, in a recording apparatus such as an electrophotographic copying apparatus, the ratio of toner transfer from a toner retaining member to a transfer member does not reach 100%. Therefore, if such a conventional type of recording apparatus continues the toner transfer process, it has the shortcoming that toner remains on a toner retaining member and thus remaining toner is also transferred onto a non-image area of the next transfer member. Therefore, it is necessary to clean up toner remaining on a toner remaining member after a transfer process is completed.
As for a cleaning apparatus for the above purpose, a variety of means have so far been proposed. For example, there have been adopted the fur brush type cleaning method, web type cleaning method, roller type cleaning method and blade type cleaning method. If the toner having been cleaned remains uncollected in a toner reservoir or a toner conveyance means, it causes the shortcomings that said toner is scattered in the apparatus and causes a contamination, and besided that, for example, said toner adheres again onto a toner retaining member before the toner will transfer thereon and thus an image quality becomes worse or a toner cleaning apparatus is overloaded thereby. Accordingly, it is required to collect the toner having been cleaned into a toner reservoir or a toner conveyance means. Therefore, in a toner cleaning apparatus, it is required that the toner remaining on a toner retaining member can be cleaned and that the toner can be collected.
Conventionally, there has so far been known the cleaning apparatus as shown in FIG. 1 and FIG. 2 respectively.
In FIG. 1, the numeral 1 indicates a toner retaining member such as a photoconductor or an insulator, 2 indicates a toner cleaning blade for cleaning toner remaining on a toner retaining member 3, indicates a toner guide member for collecting toner having been cleaned off by the toner cleaning blade 2 and 4 indicates a toner reservoir for storing toner having been collected.
Next, referring to the operation of said apparatus as shown in FIG. 1, toner retaining member 1 rotates in the direction of the arrow, developed to form a toner image, with toner, from an electrostatic latent image having been formed by an optical or an electrical means, and then transfers the thus obtained toner image onto an image transfer material. The toner still remaining on said toner retaining member after a toner image was transferred, passes through toner guide member 3 and the contact surface of toner retaining member 1, and is cleaned off by a cleaning blade 2, and then drops down along the toner retaining member. The thus dropped toner is collected by toner guide member 3 and guided to the toner reservoir. Said guide member 3 is required to collect surely all the remaining toners having been collected by the cleaning blade, without emission, into the toner reservoir. Conventionally, as for said toner guide members, a comparatively thin elastic sheet, for example, a Mylar (a trademark of E. I. Dupont) sheet of 0.1 mm in thickness, is used by bringing it into light contact with a toner retaining member. This method has the advantages that the mechanism thereof is simple and the durability of said elastic sheet serving as a toner guide member is longer. However on the other hand, it has also the essential disadvantages, that it is required to press said elastic sheet forcibly into contact with a toner retaining member in order to reduce the toner leakage, and consequently said toner retaining member 1 is damaged and an image quality is worsened. Further, according to environmental conditions, the front end of said elastic sheet becomes wavy, (i.e., the so-called "wavy phenomenon"), and thus said sheet cannot come into contact with a toner retaining member uniformly, and consequently, for example, the leakage of toner will contaminate the inside of the apparatus. There is also the disadvantage such as a strict requirement in preciseness of processing and fitting of said elastic sheet.
FIG. 2 shows a cleaning apparatus using a roller serving as to a toner guide member. The reference numerals, 1, 2 and 4 are the same as in FIG. 1, so that the explanations thereof are omitted herein. Numeral 5 indicates a roller made of metal, elastic materials or the like. Numeral 6 indicates a scraper for scraping the toner adhered onto and then collected by roller 5 and for collecting them. Roller 5 is brought into light contact with a toner retaining member and is rotated in the direction of the arrow. Next, referring to the operations of the means shown in FIG. 2, a toner image having been formed on a toner remaining member in the similar manner to that in the description of FIG. 1, is transferred onto a toner transfer member, and thereafter, the toner remaining on said toner retaining member passes through roller 5 and the contact surface of said toner retaining member, and then drops down along toner retaining member 1. Thus dropped toner is adhered onto and collected by roller 5, and the toner adhered onto and collected by said roller 5, is scraped by scraper 6 and collected into toner reservoir 4. The apparatus shown in FIG. 2 has the advantage that the so-called wavy phenomenon does not result on the roller and therefore that no toner leakage is caused by said phenomenon, in contrast with the apparatus shown in FIG. 1. On the contrary, this apparatus has the problems that a toner filming phenomenon is caused on a toner retaining member by said roller and thus an image quality is worsened, or that scraper 6 has a resemblance to said elastic sheet 3 in the structure, therefore the so-called wavy phenomenon is caused, and the toner on roller 5 cannot completely be collected, and then the toner adhered on said roller 5 remains and solidifies, thus damaging the toner retaining member. Further, this arrangement has the additional disadvantage that very highly fitting preciseness is requested to fit roller 5.
As for one of the methods of solving the disadvantages in said toner guide members, for example, the method described in Japanese Patent Publication Open to Public Inspection No. 71646/1979 has been proposed.
In this method, a bristlelike or porously elastic body is arranged on a portion coming into contact with a toner retaining member of a toner guide member, and the toner having been caught in the vacant spaces inside said bristlelike or porously elastic body, is scraped by a rotating brush and then collected in a toner reservoir. According to said method, there becomes less of a possibility of damage to a toner retaining member by a toner guide member. On the other hand, this method needs a rotating brush in order to catch and scrape toner in the vacant spaces inside said bristlelike or porously elastic body of the toner guide member. Therefore, the device is larger in size and increases the costs thereof. Further, due to a frictional charge or the like generated in the area between said rotating brush and the bristlelike or porously elastic body of the toner guide member, this method has the disadvantage that toners is adhered and solidified on said area and the toner retaining member is damaged. Also this method has the other disadvantages that the toner remaining on the toner retaining member contaminates the inside of the apparatus, because said toners is scraped on the surface of said bristlelike or porously elastic body to where the toner retaining member is brought into contact with said elastic body, and that the toners remaining thereon is trapped and cohered together, and consequently the toner retaining member is damaged.